With hurricane season underway, several regions of the United States face the threat of wind-related damage to buildings. According to the Insurance Institute for Business and Home Safety (IBHS), high winds cause millions of dollars in property damage each year, with roofs representing 85 to 95 percent of those losses. The good news is that much of this damage can be avoided through quality design and new construction methods that are available to strengthen wood structures, including roofs, against wind damage.
To help address the design challenges associated with high wind, the American Wood Council (AWC) has developed a series of Guides to Wood Construction in High Wind Areas. The guides establish a specific set of prescriptive, wind-resistive structural requirements for wood-frame buildings of certain sizes and shapes. The provisions of the guides, developed specifically for builders, are focused on ensuring structural integrity in resisting wind loads in compliance with the International Building Code (IBC) and International Residential Code (IRC), which are the model codes adopted in most jurisdictions.
Often characterized by repetitive-member framing and robust connections, wood buildings inherently meet the challenges of high wind impacts. Notably, wood structural materials can carry substantially greater maximum loads for short durations that are often found during high wind events. Additionally, when structural panels such as plywood or oriented strand board (OSB) are properly attached to floor, roof and wall framing, they form very strong diaphragms and shear walls that are exceptional at resisting high winds.
The guides from AWC recognize these benefits, while translating what is required by national model building codes for high wind. Separate documents are available that address wind design requirements for 115-, 120-, 130-, 140-, 150- and 160-miles-per-hour (Exposures B and C) wind zones. Areas particularly vulnerable to hurricanes include the U.S. Atlantic and Gulf of Mexico coasts where even basic design wind speeds are greater than 115 mph.
Many in our industry have the opportunity to engage directly with builders, architects, and engineers who are faced with the challenge of designing durable buildings. With the hurricane season upon us, I encourage you to help educate this audience by sharing these wind guides and other resources available from the industry – help convince them that designing buildings to successfully withstand high wind forces is a core responsibility and can be achieved through use of appropriate wood construction.
The Guides to Wood Construction in High Wind Areas are available for free download at the AWC website: http://www.awc.org/codes-standards/publications/wfcm-2015.